Catalyst with an Ion-Modified Binder

ABSTRACT

A solid catalyst, such as a molecular sieve catalyst or solid acid catalyst, is supported by a binder, such as amorphous silica or alumina, wherein the binder is charged with metal ions to form an ion-modified binder. The ion-modified binder is capable of attachment to polar contaminants and inhibit their contact with the catalyst. The catalyst can be a zeolite and can be the catalyst for an alkylation reaction, such as the alkylation of benzene with ethylene.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

FIELD

The present invention generally relates to binders used with catalysts,such as a zeolite catalyst.

BACKGROUND

Binders can be added to catalytic materials to form an aggregatecatalyst with modified properties, such as improved physical properties.One type of catalyst that can be modified with a binder material is amolecular sieve type catalyst such as zeolite.

Zeolite is a crystalline alumino-silicate that is well known for itsutility in several applications. It has been used in dealkylation,transalkylation, isomerization, cracking, disproportionation, anddewaxing processes, among others. Its well-ordered structure is composedof tetrahedral AlO₄ ⁻⁵ and SiO₄ ⁻⁴ molecules bound by oxygen atoms thatform a system of pores typically on the order of 3 Å to 10 Å indiameter. These pores create a high internal surface area and allow thezeolite to selectively adsorb certain molecules while excluding others,based on the shape and size of the molecules. Thus, zeolite can becategorized as a molecular sieve. Zeolite can also be termed a “shapeselective catalyst.” The small pores can restrict reactions to certaintransition states or certain products, preventing shapes that do not fitthe contours or dimensions of the pores.

The pores in zeolite are generally occupied by water molecules andcations. Cations balance out the negative charge caused by trivalentaluminum cations which are coordinated tetrahedrally by oxygen anions.Zeolite can exchange its native cations for other cations; one exampleis the exchange of sodium ions for ammonium ions. In some ion-exchangedforms, such as the hydrogen form of zeolite, the catalyst is stronglyacidic. The acidic active sites are useful for alkylation as well asmany other reactions. For instance, zeolite can serve as a solid acidcatalyst for Friedel-Crafts alkylations, replacing traditional aluminumtrichloride and other liquid acid catalysts that can be corrosive anddamaging to the reactor.

One alkylation reaction for which zeolite can be used as a solid acidcatalyst is the alkylation of benzene with ethylene to formethylbenzene. Ethylbenzene is an aromatic hydrocarbon with the chemicalformula C₆H₅CH₂CH₃; it consists of a six-carbon aromatic ring with asingle attached ethyl group. It can undergo a dehydrogenation reactionto form the monomer styrene, the monomer from which polystyrene is made.Polystyrene is a plastic that can form many useful products, includingmolded products and foamed products, all of which increase the need forproduction of styrene's precursor, ethylbenzene.

In the ethylation of benzene, zeolite can be categorized as aheterogenous acid catalyst, because it is in a different phase than thereactants. The zeolite catalyst is solid and usually supported by analumina or silica binder to increase its mechanical stability inside thereactor bed. The reactants, on the other hand, are either in the liquid,vapor, or supercritical phase. The production of ethyl benzene viaalkylation has been done with benzene in the gaseous phase, but it isalso possible to use liquid phase alkylation, which requires lowertemperatures. Liquid phase alkylation can be more economical in certainsituations and can decrease the production of unwanted by-products.

However, operating at the lower temperatures required for liquid phasealkylation can have the effect of increasing the catalyst's sensitivityto impurities in the feedstock. The acid sites in zeolite are prone todeactivation, especially in liquid phase reactions, by polar moleculescontaining nitrogen, oxygen, and sulfur functional groups. Thedeactivation of the catalyst's acid groups decreases catalystefficiency. One result can be that the catalyst's deactivation rateincreases, necessitating more frequent catalyst regeneration andshortening the overall lifetime of the catalyst. Catalyst regenerationand replacement can both require process shutdown of the reactors,costing time and money, and thus it is desirable to perform thesefunctions infrequently.

One solution has been to filter polar poisons from the feedstock priorto its contact with the zeolite catalyst, such as by passing the feedstream through one or more molecular sieves prior to its entering themain reaction bed. In many cases, however, trace amounts of these polarcontaminants still reach the zeolite catalyst.

Because the present technology for purifying the alkylation feedstockfails to entirely prevent small amounts of polar contaminants fromentering the reaction bed, it would be desirable to inhibit thecontaminants that do enter the reaction bed from contacting the activesites of the zeolite catalyst. It is desirable to inhibit contaminantsfrom contacting the active sites of the catalyst, whether zeolite orother catalyst types.

SUMMARY

Embodiments of the present invention generally include a catalyst thatemploys a binder as a means of mechanical support, wherein the binder ismodified by the inclusion of metal ions to form an ion-modified binder.The ion-modified binder can attach to polar contaminants present in thereaction bed in such a way that inhibits contact between the polarcontaminants and the catalyst. The ion-modified binder can attach to thecontaminants without adversely affecting the catalyst or causingsignificant by-product formation at reaction conditions. Furthermore,the ion-modified binder can lengthen the overall catalyst life anddecrease the rate of deactivation of the catalyst by preventing thecontact of polar contaminants with the catalyst.

The ion-modified binder can comprise amorphous silica or alumina. Thesilica or alumina becomes “ion-modified” by the addition of metal ionsor similar species. One method of adding metals ions to a binder isincipient wetness impregnation. The metal ions can make up from 0.1% to50%, optionally from 0.1% to 20%, optionally from 0.1% to 5%, by weightof the ion-modified binder. Suitable metal ions include Co, Fe, Cu, Zn,Sn, Pb, Bi, Ba, V, Mn and similar species such as metal oxides,nanoparticles, or mixed metal oxide phases, and combinations thereof.Any metal ions, similar species, or combinations thereof that can enablea binder to absorb polar contaminants can be useful for the presentinvention.

The ion-modified binder can make up from 1% to 80%, optionally from 5%to 60%, optionally from 10% to 30%, by weight of the catalyst.Aggregates consisting of a catalyst and an ion-modified binder can beformed by mixing the catalyst and binder in the presence of volatilesand shaping the mixture via extrusion or other means to form a shapesuitable for a reaction bed. The shaped form can be dried at temperatureof from 100° C. to 200° C. and can be calcined at a temperature of from400° C. to 1000° C. in a substantially dry environment.

The catalyst formed with the ion-modified binder falls into either ofthe general categories comprising molecular sieve catalysts and solidacid catalyst. The catalyst can be a zeolite. The catalyst can be usedin many reactions, including alkylation, dealkylation, transalkylation,isomerization, cracking, disproportionation, dewaxing, andaromatization.

Alkylation reactions can take place between an aromatic substrate and analkylating agent. In one embodiment the aromatic substrate is benzeneand the alkylating agent is ethylene. The present invention can beapplied towards the alkylation of benzene with ethylene, whereinethylene and benzene are introduced into a reaction bed housing azeolite catalyst formed with an ion-modified binder. A reaction takesplace forming ethylbenzene as its main product. The alkylation can bevapor phase, liquid phase, or supercritical phase. The ethylene andbenzene feed streams can be pretreated prior to their introduction tothe reaction bed; however, polar contaminants may still be present inthe feed stream. Polar contaminants that enter the reaction bed can beabsorbed by the ion-modified binder.

An alternate embodiment of the present invention is a method forpreparing a catalyst that includes adding metal ions to a binder to forman ion-modified binder and combining the ion-modified binder with thecatalyst to form an ion-modified binder and catalyst aggregate. Thecatalyst can be used in a reaction bed for the alkylation of benzenewith ethylene. The catalyst can be a zeolite catalyst, and the bindercan be modified with ions via an incipient wetness method.

The metal ions can make up 0.1% to 50% by weight of the ion-modifiedbinder. The ion-modified binder can make up 1% to 80% by weight of thecatalyst. The metal ions can be chosen from the group consisting of Co,Fe, Cu, Zn, Sn, Pb, Bi, Ba, Mn and V, and combinations thereof. Theion-modified binder can be capable of attachment to polar contaminantsand thereby inhibit the contact of polar contaminants with the zeolite.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 charts the temperature differentials of adjacent thermocouplesalong a reactor bed using a zeolite catalyst with an unmodified binder.

FIG. 2 charts the temperature differentials of adjacent thermocouplesalong a reactor bed using a zeolite catalyst with an ion-modifiedbinder.

DETAILED DESCRIPTION

The present invention relates to the modification of a binder for acatalyst, such as a zeolite catalyst, to inhibit interaction of polarcontaminants in the reaction bed with the catalyst. Specifically, thebinder is modified by the addition of active metal ions, or othersimilar species, to capture the polar contaminants in a way thatinhibits the contaminants from contacting the catalyst and inhibitsby-product formation.

The powder form of zeolite and other catalysts can be unsuitable for usein the reactor, due to a lack of mechanical stability, making alkylationand other desired reactions difficult. To render a catalyst suitable forthe reactor, it can be combined with a binder to form an aggregate, suchas a zeolite aggregate, with enhanced mechanical stability and strength.The aggregate can then be shaped or extruded into a form suitable forthe reaction bed. The binder can desirably withstand temperature andmechanical stress and ideally does not interfere with the reactantsadsorbing to the catalyst. It is possible for the binder to formmacropores, much greater in size than the pores of the catalyst, whichcan provide improved diffusional access of the reactants to thecatalyst.

Binder materials that are suitable for the present invention include,but are not limited to, silica, alumina, titania, zirconia, zinc oxide,magnesia, boria, silica-alumina, silica-magnesia, chromia-alumina,alumina-boria, silica-zirconia, silica gel, clays, similar species, andany combinations thereof. The most frequently used binders are amorphoussilica and alumina, including gamma-, eta-, and theta-alumina. It shouldbe noted that a binder can be used with many different catalysts,including various forms of zeolite and non-zeolite catalysts thatrequire mechanical support.

According to the present invention, the binder is modified such that itprovides mechanical support and performs other typical functions of abinder, as well as limiting the contact of polar contaminants with thecatalyst. The binder of the present invention is composed of alumina orsilica or similar amorphous material and includes active metal ions orsimilar species. The active metal ions may be ions of the followingnon-limiting examples of Co, Fe, Cu, Zn, Sn, Pb, Bi, Ba, V, Mn, orsimilar species such as metal oxides, nanoparticles, or mixed metaloxide phases. Other similar metal ions and species not listed may beused, as well as combinations of any of the listed and unlisted metalions and similar species.

As used herein, the term “metal ion” is meant to include all activemetal ions and similar species, such as metal oxides, nanoparticles, andmixed metal oxide phases, capable of being added to a binder andenabling said binder to attach to polar contaminants without adverselyaffecting the catalyst that it supports or causing significantby-product formation at reaction conditions. Further, the term“ion-modified binder” as used herein refers to a binder for a catalystthat has been modified with a metal ion to attach to polar contaminants.It is desirable that the metal ions not adversely affect the catalystthat it supports or cause significant by-product formation to occur.Polar contaminants generally include polar molecules such as those withnitrogen, oxygen, and sulfur functional groups. Typical polarcontaminants encountered in the liquid phase alkylation of benzene withethylene include amines, nitriles, aldehydes, alcohols, acids, sulfurspecies, and the like. These and similar species can also becontaminants for reactions other than the alkylation of benzene withethylene.

The metal ion can be added to the binder in the amount of 0.1% to 50%,optionally 0.1% to 20%, optionally 0.1% to 5%, by weight of the binder.The metal ion can be added to the binder by any means known in the art.Generally, the method used is incipient wetness impregnation, whereinthe metal ion precursor is added to an aqueous solution, which solutionis poured over the binder. After sitting for a specified period, thebinder is dried and calcined, such that the water is removed with themetal ion deposited on the binder surface. The ion-modified binder canthen be mixed with a catalyst by any means known in the art. The mixtureis shaped via extrusion or some other method into a form such as apellet, tablet, cylinder, cloverleaf, dumbbell, symmetrical andasymmetrical polylobates, sphere, or any other shape suitable for thereaction bed. The shaped form is then usually dried and calcined. Dryingcan take place at a temperature of from 100° C. to 200° C. Calcining cantake place at a temperature of from 400° C. to 1000° C. in asubstantially dry environment. The resultant catalyst aggregate cancontain ion-modified binder in concentrations of from 1% to 80%,optionally from 5% to 50%, optionally from 10% to 30%, by weight. Thepercent weight of the catalyst that is binder is somewhat determined bythe temperature of the reaction zone in which the catalyst will be used.For example, in the use of zeolite for an alkylation reaction, about 50%zeolite and 50% binder can be used in the higher temperature alkylationcatalyst beds and about 75% zeolite and 25% binder can be used in thelower temperature alkylation catalyst beds.

For the present invention, the catalyst to be supported and protected bythe ion-modified binder can be a zeolite, but can also be a non-zeolite.Zeolite is generally a porous, crystalline alumino-silicate, and it canbe formed either naturally or synthetically. One method of formingsynthetic zeolite is the hydrothermal digestion of silica, alumina,sodium or other alkyl metal oxide, and an organic templating agent. Theamounts of each reactant and the inclusion of various metal oxides canlead to several different synthetic zeolite compositions. Furthermore,zeolite is commonly altered through a variety of methods to adjustcharacteristics such as pore size, structure, activity, acidity, andsilica/alumina molar ratio. Thus, a number of different forms of zeoliteare available. Different classes of zeolite and zeolite-like catalystsinclude the types zeolite A, zeolite X, zeolite Y, zeolite L, zeolitebeta, zeolite omega, zeolite Z, ZSM-3, ZSM-4, ZSM-5, ZSM-11, ZSM-12,ZSM-18, ZSM-20, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, ZSM-50, MCM-22,MCM-36, MCM-49, MCM-56, MCM-58, MCM-68, ITQ-1, ITQ-2, PSH-3, SSZ-25,ERB-1, ERB-3, NU-10, Theta 1, TS-1, as well as faujasite, mordenite,chabazite, offretite, clinoptilolite, erionite, sihealite, and the like.It is possible to generate crystals that are not alumino-silicates butbehave similarly to zeolite, including aluminophosphates such as ALPO-5and VPI-5, metalosilicophosphates, silicoaluminophosphates such asSAPO-5, SAPO-31, SAPO-34, SAPO-37, SAPO-40, and SAPO-41, porouscrystalline magnesium silicates, and tungstate modified zirconia. Otherelements, including boron, gallium, iron and germanium, have also beenused to replace the aluminum or silicon in the framework structure ofzeolite.

Another method of altering zeolite is by ion-exchange. For example, thehydrogen form of zeolite can be produced by ion-exchanging beta zeolitewith ammonium ions. Metal ions can also be incorporated into zeolite,either by ion-exchange or another method. Examples of such metal ionpromoters include cerium, lanthanum, and other metals from thelanthanide series. It has also been reported that “as-synthesized” Nazeolite can be ion-exchanged to include IA, IIA or IIIA metals, such asions of lithium, potassium, calcium, magnesium, lanthanum, cerium,nickel, platinum, palladium, and the like. Other metals that may be usedwith zeolite include those from the groups IIB, III, IV, V, VI, VIIA andVIII, and the like. Specific non-limiting examples include Group IIA(Mg, Ca, Sr, Ba), Group IIIA (B, Al, Ga, In), Group IIIB (Sc, Y, and thelanthanide elements), Group IVB (Ti, Zr, Hf), Group VB (V, Nb, Ta),Group VIB (Cr, Mo, W), and Group VIIB (Mn, Tc, Re) of the Periodic Tableof the Elements. Halogens are also possible inclusions in the zeoliteframework. Further, the silica/alumina ratio of the zeolite can bealtered, via a variety of methods, such as dealumination by steaming oracid washing to increase the silica/alumina ratio. Increasing the amountof silica relative to alumina can have the effect of increasing thecatalyst hydrophobicity. The silica/alumina ratio can range from lessthan 0.5 to 500 or greater. Some catalysts other than zeolite can alsobe used with a binder of the present invention, including catalysts thatfall into the general categories of molecular sieves and/or solid acidcatalysts.

Thus, a variety of zeolites and non-zeolites are available for use inconjunction with the ion-modified binder of the present invention. Thevarious catalysts listed in the two preceding paragraphs are not meantto be an exhaustive list, but is meant to indicate the type of catalystsfor which an ion-modified binder can be useful. The choice of catalystwill depend on the reaction type and the reaction conditions in which itwill be used. One skilled in the art can select any zeolite ornon-zeolite catalyst that meets the needs of the intended reaction,provided that an ion-modified binder can be used to support the catalystand inhibit polar contaminants from interfering with the catalyst.

Processes for which an ion-modified binder can be used include, but arenot limited to, oxidation, reduction, adsorption, dimerization,oligomerization, polymerization, etherification, esterification,hydration, dehydration, condensation, acetalization, dealkylation,cyclization, alkylation, hydrodealkylation, exhaust gas cleaning,transalkylation, isomerization, cracking, disproportionation, dewaxing,hydroisomerization, hydrocracking, aromatization, and any processemploying a molecular sieve or solid acid catalyst in which contactbetween the catalyst and polar contaminants is wished to be reduced. Onecommon process is alkylation.

Many different forms of alkylation reactions are possible. In general,alkylation occurs when an alkylating agent consisting of one or morecarbon atoms is added to an alkylatable substrate. Alkylating agentsthat can be used in alkylation reactions are generally olefins. Anolefin can be short chain, like ethylene, propylene, butene, andpentene, or it can be long chain with a higher number of carbon atoms.It can be an alpha olefin, an isomerized olefin, a branched-chain olefinor a mixture thereof. Alkylating agents other than olefins includealkynes, alkyl halides, alcohols, ethers, and esters. In some cases, thealkylating agent is diluted with a diluting agent prior to itsintroduction into the reaction bed. Especially for ethylene, dilutingagents such as inert, or nonreactive, gases like nitrogen have beenreported, with the concentration of the diluting agent greater than theconcentration of the alkylating agent in the diluted feedstream,optionally around 70% diluting agent and 30% alkylating agent.

The alkylatable substrate is usually an unsaturated hydrocarbon or anaromatic. If the alkylatable substrate is an aromatic compound, it canbe unsubstituted, monosubstituted, or polysubstituted, and it possessesat least one hydrogen atom bonded directly to the aromatic nucleus orsome other site that will allow for alkylation to occur. The aromaticnucleus can be benzene or a compound comprising more than one aromaticring, like naphthalene, anthracene, naphthacene, perylene, coronene, andphenanthrene. Compounds that have an aromatic character but contain aheteroatom in the ring can also be used, provided they will not causeunwanted side reactions. Substituents on the aromatic nucleus can bealkyl, hydroxy, alkoxy, aryl, alkaryl, aryloxy, cycloalkyl, halide,and/or other groups which do not interfere with the alkylation reactionand that comprise 1 to 20 carbon atoms. Aromatic substrates that may bealkylated by an alkylating agent include toluene, xylene, biphenyl,ethylbenzene, isopropylbenzene, normal propylbenzene, butylbenzene,pentylbenzene, hexylbenzene, heptylbenzene, octylbenzene, nonylbenzene,dodecylbenzene, pentadecylbenzene, hexyltoluene, nonyltoluene,dodecyltoluene, pentadecytoluene, alpha-methylnaphthalene, mesitylene,durene, cymene, pseudocumene, diethylbenzene, isoamylbenzene,isohexylbenzene, pentaethylbenzene, pentamethylbenzene,tetraethylbenzene, tetramethylbenzene, triethylbenzene,trimethylbenzene, butyltoluene, diethyltoluene, ethyltoluene,propyltoluene, dimethylnaphthalenes, ethylnaphthalene,dimethylanthracene, ethylanthracene, methylanthracene,dimethylphenanthrene, phenanthrenephenol, cresol, anisole,ethoxybenzene, propoxybenzene, butoxybenzene, pentoxybenzene,hexoxybenzene, any isomers thereof, and the like. One common alkylationreaction towards which the present invention can be applied is thealkylation of benzene with propylene to produce cumene.

Another common alkylation reaction for which the present invention isuseful is the alkylation of benzene with ethylene over a solid acidcatalyst. Reactants for the ethylation of benzene generally includeethylene as the alkylating agent and benzene as the alkylatablesubstrate. The source of both reactants is generally refined petroleum,but each can come from other sources as well. Depending on the source,the reactants may have varying levels of purity. Ethylene is generallyrecovered from hydrocarbon cracking and goes through repeated cycles ofdistillation until a desired level of purity is obtained. The purity maybe as high as or higher than polymer grade ethylene, 99.5%. However,less pure or diluted ethylene can be used. For example, dilute ethylenecan contain 50% or more impurities, which can be made up of mostlyethane and a small amount of hydrogen or methane. As previouslymentioned, ethylene can also be diluted with an inert gas. Both ethyleneand benzene can be diluted with diluents such as ethane, mixed hexanes,mixed butanes, and the like. The purity level of benzene can vary aswell. Most prior art teachings suggest a purity greater than 90%,optionally 98% or more. The contaminants in the benzene feed stream caninclude toluene, ethylbenzene, and C-7 hydrocarbons that are not easilyseparated from benzene.

The feed stream containing the reactants can be treated for the removalof contaminants prior to its introduction into the reaction bed. Variousforms of feed stream pretreatment can remove contaminants such asolefins, diolefins, styrene, oxygenated organic compounds,sulfur-containing compounds, nitrogen-containing compounds, andoligomeric compounds. One method is the use of a large pore molecularsieve catalyst to remove impurities prior to the alkylation reaction.The molecular sieve can be placed, for example, in a reactive guard bed,in which the alkylation reaction occurs along with the capture ofcontaminants. This reactive guard bed can be equipped with a by-pass, sothat the molecular sieve can undergo regeneration without interruptingthe reaction in the main alkylation reactor beds. Despite pretreatment,some polar contaminants may still reach the reaction bed.

The reactants ethylene and benzene can enter the reactor via a singleinlet or separate inlets. The reactants can be delivered to the reactionbed in the gaseous phase, the liquid phase, a combination of liquid andgaseous phase, the supercritical phase, or a combination of liquid andsupercritical phases. The reaction conditions, including reactor type,pressure, temperature, liquid hourly space velocity (LHSV), and benzeneto ethylene ratio depend in part on the phase in which the alkylation isto occur.

For vapor phase alkylation, the reactions conditions generally include atemperature of from about 270° C. to 400° C., a pressure of from about200 psig to 600 psig, a LHSV of from about 10 hr⁻¹ to 70 hr⁻¹, and abenzene to ethylene ratio of from about 3:1 to 20:1. Further, gas phasealkylation is generally performed with a reactor operated in a down-flowmode but can use another flow type.

For liquid phase alkylation, the reaction zone is operated at suchtemperature and pressure to maintain essentially liquid phaseconditions. For the production of ethylbenzene, the reaction temperaturemay range from about 40° C. to 320° C., and is generally between about120° C. and 280° C. The alkylation pressure is generally kept highenough to ensure a liquid phase. In one embodiment the pressures canrange from 300 psig to 1600 psig, or up to 3000 psig, in an alternateembodiment the pressures can range from 500 psig to 1000 psig. Flowrates typically can range from liquid hourly space velocity (LHSV)between about 1 and 100 hr⁻¹ per bed and an aromatic benzene to ethylenemolar ratio between about 1:1 and 100:1. In one embodiment LHSV'sbetween about 10 to 70 hr⁻¹ per bed and benzene to ethylene molar ratiosbetween about 2:1 to 50:1 are used. In another embodiment an LHSV offrom about 10 hr⁻¹ to 70 hr⁻¹, and a benzene to ethylene molar ratio offrom about 3:1 to 20:1 can be used. Further, liquid phase alkylation isgenerally performed with an up-flow reactor but can be performed withanother flow type. If the pressure is not high enough, the reactants, inparticular benzene, can be partially in the liquid phase and partiallyin the vapor phase.

For supercritical phase alkylation, the reaction conditions generallyinclude pressure and temperature conditions which are above the criticalpoint for benzene. Specifically, the temperature in the alkylation zoneis at or above 280° C., and the pressure is at or above 550 psig. Ingeneral, the reaction conditions can involve a temperature of from about300° C. to 600° C., a pressure of from about 550 psia to 850 psia, aLHSV of from about 10 hr⁻¹ to 150 hr⁻¹, and benzene to ethylene ratio offrom about 1:1 to 15:1. Under such conditions, it is possible to havesome benzene present in both the liquid and the supercritical phases.

In general, the reactor scheme can be any one that is known in the artto be useful. For instance, either a single stage reactor or a multiplestage reactor with several reactor beds in series can be used. Formultiple stage reactors, it is possible to have interstage injection ofethylene and benzene, as well as interstage cooling, between catalystbeds. A reactor can have an upward flow, a downward flow, or ahorizontal flow configuration. The reaction beds can be fixed, swing,moving, or some other type. The reactor optionally can include heatexchangers, thermocouples, or any other supplemental devices known inthe art to be useful. It can include an outlet for the reactionproducts. This outlet can to lead to a separation and recovery zone, inwhich ethylbenzene and other effluents like unreacted ethylene orbenzene and diethyl and polyethyl benzene are separated, generally bydistillation. A recycle stream can be included for certain products,such as diethylbenzene and polyethylated benzenes, to either return tothe main reactor bed or be introduced into a new reactor fortransalkylation. Transalkylation is a reaction in which the alkylatablesubstrate, in this case benzene, and polyalkylated effluent, in thiscase polyethyl benzene, react over a molecular sieve or solid acidcatalyst like zeolite to form monoalkylated effluent, in this caseethylbenzene. Transalkylation reactions can be performed in eitherliquid or vapor phase and can use either the same or a differentcatalyst from the alkylation catalyst.

After a period of running the alkylation reactions, deactivation of thecatalyst can occur. Catalyst deactivation can be due to coke formationon the catalyst bed, which is in part due to the exothermic nature ofthe alkylation reaction. The degree of deactivation can be determined inpart by measuring the exotherm as it moves through the catalyst bed fromthe inlet side to the outlet side of the reactor. Exotherm can bemeasured, for instance, by measuring the temperature differentialsbetween adjacent thermocouples placed along the reaction bed. Anothercause of catalyst deactivation can be the polymerization of the olefinicalkylating agent, ethylene. The large oligomers cannot diffuse out ofthe pores containing the active sites in the zeolitic material and cancause the zeolite to lose its catalytic activity. Deactivation can alsobe caused by the polar contaminants which have been previously discussedand are the target of the ion-modified binder of this invention.

Zeolite deactivation generally requires a regeneration procedure to beperformed. Some methods of regenerating zeolite include heating toremove adsorbed materials, ion exchanging with sodium to remove unwantedcations, or pressure swing to remove adsorbed gases. One solutioninvolves flushing the catalyst with benzene. Other solutions generallyinvolve processing the catalyst at high temperatures using regenerationgas and oxygen. According to one procedure, a zeolite beta can beregenerated by heating the catalyst first to a temperature in excess of300° C. in an oxygen-free environment. Then an oxidative regenerationgas can be supplied to the catalyst bed with oxidation of a portion of arelatively porous coke component to produce an exotherm moving throughthe catalyst bed. Either the temperature or the oxygen content of thegas can be progressively increased to oxidize a porous component of thecoke. Again, regeneration gas can be supplied, wherein the gas haseither increased oxygen content or increased temperature to oxidize aless porous refractory component of the coke. The regeneration processcan be completed by passing an inert gas through the catalyst bed at areduced temperature. One benefit of the ion-modified binder of thepresent inventions can be that oxygen-activating metal ions, if presentin the binder, can enhance regeneration.

In one aspect, the present invention is for a zeolite catalyst forethylbenzene alkylation, wherein the zeolite is supported by anion-modified binder. In another aspect, the present invention is for abinder for a molecular sieve or solid acid catalyst, wherein said binderis ion-modified such that it inhibits polar contaminants in the reactionbed from reaching said catalyst and does not result in significantby-product formation at reaction conditions. In another aspect, thepresent invention is a method of preparing a zeolite catalyst with anion-modified binder, comprising the steps of: adding an amount of metalion to a binder via incipient wetness impregnation, mixing theion-modified binder with zeolite catalyst to form a catalyst aggregate,shaping the catalyst aggregate into a shape suitable for an alkylationreactor bed, and drying and calcining the shaped catalyst aggregate. Instill another aspect, the present invention is a method for theproduction of ethylbenzene, comprising the steps of: contacting ethylenewith benzene in the presence of a zeolite catalyst in a liquid phasereaction zone, wherein said zeolite is supported by an ion-modifiedbinder; and recovering ethylbenzene effluent from the reaction zone.

Zeolite catalysts prepared with an ion-modified binder can show improvedcatalytic performance and catalyst lifetime. Further, the deactivationrate and by-product formation can be reduced. These improvements canoccur as a result of decreased contact between the catalyst and polarcontaminants. The following example demonstrates the properties of azeolite catalyst supported by an ion-modified binder and exemplifies themethods for producing said binder and said catalyst. This example is notmeant to reduce the scope of the present invention, but merely describeone particular embodiment.

Two zeolite catalysts were prepared, both employing alumina binders. Inone catalyst, the alumina was modified by adding cobalt nitrate viaincipient wetness impregnation to the alumina to form an ion-modifiedbinder. The other catalyst was formed with an unmodified binder in orderto serve as a reference. Other than the addition of cobalt ions to thebinder of one of the catalysts, the two catalysts were prepared usingthe same ingredients and procedures. Herein, the reference catalystshall be referred to as “catalyst A”, while the catalyst containing anion-modified binder shall be referred to as “catalyst B”.

The reference catalyst, or catalyst A, was prepared by placing 24 g ofZ-SAR300 H-beta powder and 6 g of gamma alumina (Alfa Aesar #39812, 3micron, 80-120 m²/g) in a beaker and mixing. To the same beaker 0.3 g ofgraphite powder was added and mixed in. Water was poured into a separatebeaker containing 1.25 g of sugar until a total mass of 5 g was reached,to form a 25% aqueous sugar solution. The sugar solution was added dropwise to the beaker containing the zeolite and alumina powder until aviscous solution of a consistency similar to cake mix formed. A 13 mmdie and a Carver press were used to form pellets from the viscoussolution. The pellets were then calcined by placing them in a ceramicdish in a calcining furnace, at ˜115° C. for one hour initially. At theend of the hour, the temperature was increased by 50° C. every 30minutes until a temperature of 500° C. was reached, at which point thetemperature was held constant for two hours. The catalyst was thenremoved from the furnace, cooled, and stored in a sealed bottle. Later,the catalyst was crushed and sieved to a 40-60 mesh for use in thealkylation reactor.

The other catalyst, catalyst B, was prepared according to the sameprocedure, except that 6 g of an ion-modified binder was used in theplace of 6 g of unmodified gamma alumina. The ion-modified binder was0.5% Co on gamma alumina. It was prepared by adding 0.49 g ofCo(NO₃)₂-6aq to 16.1 mL of deionized water in a beaker and stirringuntil dissolved. The solution was added a few drops at a time to anotherbeaker containing 20 g of dry gamma alumina, all the while mixing well.The mixture was left open to the atmosphere for two hours. The mixturewas dried overnight at 100-120° C. After drying, the binder was calcinedat 450° C. for four hours and crushed and sieved to less than 350 mesh.The resultant ion-modified binder was then used to prepare a zeolitecatalyst according to the same procedure as described in the precedingparagraph.

Catalysts A and B were evaluated in a laboratory reactor for the liquidphase alkylation of benzene with ethylene. A 10 mL catalyst bed packedwith 40-60 mesh of the catalyst was loaded into a tubular up-flowreactor. The experimental conditions were 72 hr⁻¹ LHSV, an 18 molarratio of benzene to ethylene, a pressure of 500 psig, a temperature of200° C. for the benzene flow, and daily gas chromatography analysis. Thereaction was monitored by observing the exotherm using thermocouplesplaced at 20% sections of the catalyst bed. The exotherm created in eachzone was estimated by temperature difference (delta T) in adjacentthermocouples. The data from the initial run of catalysts A and B isshown in FIG. 1 and is included in Table 1.

FIG. 1 illustrates the temperature differential of adjacentthermocouples placed along the catalyst bed. Percent of catalyst bedappears on the x-axis and delta T in ° C. appears on the y-axis. Theexotherm of the zeolite catalyst is estimated by the temperaturedifferentials of adjacent thermocouples and is represented by the curvesappearing in the chart.

As indicated by FIG. 1, both catalysts were active during all days ofoperation. Catalyst B achieved a greater exotherm than did catalyst A onboth the first and second days of operation. The larger, broaderexotherm for catalyst B could be due to slightly elevated ethylene flow.

Further, both catalysts show some amount of deactivation on the secondday of operation, as indicated by the difference in exotherm between thefirst and second days of operation. Catalyst B shows less of differencein exotherm between the first and second day than does Catalyst A,indicating that catalyst B experienced less deactivation on the secondday than did catalyst A. Thus, a zeolite catalyst containing anion-modified binder can be more resistant to deactivation than a zeolitecatalyst containing an unmodified binder.

Not indicated by FIG. 1, was that on the second day, the referencecatalyst A produced 5.3% diethylbenzene (DEB) relative to ethylbenzene,while catalyst B produced only 3.1%. DEB and other polyalkylatedbenzenes are by-products commonly produced from the alkylation ofbenzene. It is generally desirable to reduce the number of suchby-products and to maximize the percent of products leaving the reactionbed that are the desired product, ethylbenzene. Catalyst B, with itsion-modified binder, produced less DEB by-product than did catalyst A,showing better selectivity along with its slower rate of deactivation.

Catalysts A and B were regenerated in the reactor using diluted air (2%)at 510° C. A benefit of the ion-modified binder is that regeneration canbe improved if the added metal ions can activate oxygen. Cobalt is onemetal known to have such properties. After regeneration, alkylationreactions were repeated, according to the same reaction conditions asbefore. The results are displayed in FIG. 2 and included in Table 1.

FIG. 2 is a chart, similar to FIG. 1, which illustrates the temperaturedifferential of adjacent thermocouples along the catalyst bed. Percentof catalyst bed appears on the x-axis and delta T in ° C. appears on they-axis. The exotherm of the zeolite catalyst is estimated by thetemperature differentials of adjacent thermocouples and is representedby the curves appearing in the chart. According to FIG. 2, bothcatalysts were active on all days of operation after undergoingregeneration. For catalyst A, the difference in the exotherm between thefirst and second days of operation was moderate, indicating a moderatelevel of deactivation. For catalyst B, the difference in the exothermbetween the first and second days of operation was minimal, indicating avery low level of, if not zero, deactivation.

The percent of DEB produced on the second day was 4.1% for catalyst A,and 3.2% for catalyst B. The experiments after regeneration indicateagain that catalyst B is more selective and more resistant todeactivation than is catalyst A.

The experimental data for catalysts A and B are listed in Table 1,temperatures and temperature differentials are in ° C.

TABLE 1 Catalyst A Initial Runs Regenerated Runs Day 1 Day 2 Day 3 Day 1Day 2 Day 3 TE 105 C. 226 224 222 223 223 225 TE 106 C. 227 225 223 224225 226 TE 107 C. 227 224 222 224 224 225 TE 108 C. 223 220 218 220 220219 TE 109 C. 214 211 210 212 211 210 TE 110 C. 204 203 202 203 203 202Temperature Differentials 0 0 0 0 0 0 0 20 10 8 8 9 8 8 40 9 9 8 8 9 960 4 4 4 4 4 6 80 0 1 1 0 1 1 100 −1 −1 −1 −1 −2 −1 Catalyst B InitialRuns Regenerated Runs Day 1 Day 2 Day 1 Day 2 TE 105 C. 224 220 217 216TE 106 C. 222 218 217 216 TE 107 C. 219 215 216 215 TE 108 C. 210 206210 209 TE 109 C. 198 195 200 199 TE 110 C. 186 184 190 189 TemperatureDifferentials 0 0 0 0 0 20 12 11 10 10 40 12 11 10 10 60 9 9 6 6 80 3 31 1 100 2 2 0 0

According to the example given, the use of an ion-modified binder toabsorb polar contaminants can improve catalytic performance andlifetime, and can also reduce the deactivation rate and by-productformation. Additionally, the use of oxygen-activating metal ions in theion-modified binder can enhance regeneration. The use of an ion-modifiedbinder according to the present invention can be applied to any processinvolving zeolite catalysts, molecular sieve catalysts, and solid acidcatalysts that are prone to contamination by polar molecules. Manyparameters such as reaction type, zeolite type, and reaction conditionsmay be altered without departing from the scope of the invention.

The term “deactivated catalyst” refers to a catalyst that has lostenough catalyst activity to no longer be efficient in a specifiedprocess. Such efficiency is determined by individual process parameters.

The term “ion-modified binder” as used herein refers to a binder for acatalyst that has been modified with a metal ion.

The term “molecular sieve” refers to a material having a fixed,open-network structure, usually crystalline, that may be used toseparate hydrocarbons or other mixtures by selective occlusion of one ormore of the constituents, or may be used as a catalyst in a catalyticconversion process.

Use of the term “optionally” with respect to any element of a claim isintended to mean that the subject element is required, or alternatively,is not required. Both alternatives are intended to be within the scopeof the claim. Use of broader terms such as comprises, includes, having,etc. should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

The term “regenerated catalyst” refers to a catalyst that has regainedenough activity to be efficient in a specified process. Such efficiencyis determined by individual process parameters.

The term “regeneration” refers to a process for renewing catalystactivity and/or making a catalyst reusable after its activity hasreached an unacceptable/inefficient level. Examples of such regenerationmay include passing steam over a catalyst bed or burning off carbonresidue, for example.

The term “transalkylation” refers to the transfer of an alkyl group fromone aromatic molecule to another.

The term “zeolite” refers to a molecular sieve containing a silicatelattice, usually in association with some aluminum, boron, gallium,iron, and/or titanium, for example. In the following discussion andthroughout this disclosure, the terms molecular sieve and zeolite willbe used more or less interchangeably. One skilled in the art willrecognize that the teachings relating to zeolites are also applicable tothe more general class of materials called molecular sieves.

Depending on the context, all references herein to the “invention” mayin some cases refer to certain specific embodiments only. In other casesit may refer to subject matter recited in one or more, but notnecessarily all, of the claims. While the foregoing is directed toembodiments, versions and examples of the present invention, which areincluded to enable a person of ordinary skill in the art to make and usethe inventions when the information in this patent is combined withavailable information and technology, the inventions are not limited toonly these particular embodiments, versions and examples. Other andfurther embodiments, versions and examples of the invention may bedevised without departing from the basic scope thereof and the scopethereof is determined by the claims that follow.

1. A catalyst comprising: a catalyst component; and a binder componentproviding mechanical support for the catalyst component: wherein saidbinder component is an ion-modified binder having at least one activemetal species.
 2. The catalyst according to claim 1, wherein theion-modified binder is capable of attachment to polar contaminants andthereby inhibit the contact of polar contaminants with the catalystcomponent.
 3. The catalyst according to claim 2, wherein theion-modified binder inhibits the polar contaminants contact with thecatalyst component without significant reduction of the catalystcomponent activity or causing significant by-product formation during areaction.
 4. The catalyst according to claim 1, wherein the binder iscomposed primarily of amorphous silica or alumina.
 5. The catalystaccording to claim 1, wherein metal ions make up 0.1% to 50% by weightof the ion-modified binder.
 6. The catalyst according to claim 1,wherein the metal ions make up 0.1% to 20% by weight of the ion-modifiedbinder.
 7. The catalyst according to claim 5, wherein the metal ions arechosen from the group consisting of Co, Fe, Cu, Zn, Sn, Pb, Bi, Ba, Mn,V, and combinations thereof.
 8. The catalyst according to claim 1,wherein the ion-modified binder makes up from 1% to 80% by weight of thecatalyst.
 9. The catalyst according to claim 1, wherein the ion-modifiedbinder makes up from 5% to 60% by weight of the catalyst.
 10. Thecatalyst according to claim 1, wherein the catalyst is a solid acidcatalyst.
 11. The catalyst according to claim 1, wherein the catalyst isa molecular sieve catalyst.
 12. The catalyst according to claim 1,wherein the catalyst is zeolite.
 13. The catalyst according to claim 1that catalyzes the alkylation of an aromatic substrate with analkylating agent.
 14. The catalyst according to claim 13, wherein thearomatic substrate is benzene and the alkylating agent is ethylene. 15.A method for preparing a catalyst, comprising: adding metal ions to abinder to form an ion-modified binder; and combining said ion-modifiedbinder with catalyst to form a ion-modified binder catalyst aggregate.16. The method according to claim 15, wherein the catalyst is a zeolite.17. The method according to claim 15, wherein the metal ions are addedto the binder by an incipient wetness method.
 18. The method accordingto claim 15, wherein the zeolite catalyst can be used in a reaction bedfor the alkylation of benzene with ethylene.
 19. The method according toclaim 15, wherein metal ions make up 0.1% to 50% by weight of theion-modified binder.
 20. The method according to claim 15, wherein theion-modified binder makes up 1% to 80% by weight of the catalyst. 21.The method according to claim 15, wherein the metal ions are chosen fromthe group consisting of Co, Fe, Cu, Zn, Sn, Pb, Bi, Ba, Mn, V, andcombinations thereof.
 22. The method according to claim 15, wherein theion-modified binder is capable of attachment to polar contaminants andthereby inhibit the contact of polar contaminants with the zeolite.